Muhammad Muntasir Mahmud, Wahidu Zzaman, Mohammad Tofajjal Hossain, Juwita Ratna Dewi, Nurul Huda
Probiotics are healthy living bacteria used as food additives to confer health benefits in the host. Bacteria are also used as starter cultures in the production of various foods. Recently, it has been used as a stimulator to boost human immunity and reduce intestinal inflammation. In the present study, a total of eight probiotic lactic acid bacteria were isolated from raw cow milk. All isolates were gram-positive, catalase-negative, non-motile, and had bile salt hydrolase activity, indicative of probiotic bacteria, as determined by morphological, physiological, and biochemical tests. The strains demonstrated strong gastrointestinal tolerance: each survived exposure to simulated gastric juice at pH 3.0 with minimal viability loss, and all grew in 0.3% (w/v) bile for 4h, simulating intestinal conditions. Notably, strain LB5 achieved an OD560 of ~0.28 after 4h in 0.3% bile, indicating robust bile resistance. The best phenol tolerance was observed at 0.1-0.2% phenol, and increasing incubation time (24 and 48 hours) resulted in enhanced organic acid production. The isolates fermented various sugars, benefiting lactose-intolerant people. Yogurt with isolates LB2 and LB5 scored 7.7 ± 0.47a and 7.6 ± 0.50b (“liked very much”) on a 9-point hedonic scale in terms of overall acceptance. This indicates their strong probiotic traits and suitability as adjunct yogurt cultures. LB2 and LB5 show promise for enhancing nutritional and functional quality. Their incorporation in dairy products could deliver added health benefits to consumers and the food industry.
Department of Food Engineering and Tea Technology, Shahjalal University of Science and Technology, Sylhet, Bangladesh; Bangladesh Agricultural Research Institute, Gazipur, Bangladesh; Postgraduate School, Universitas Brawijaya, East Java, Malang, Indonesia
